Towards the end of the 1920s Beretta had a range of three models of pistols, of which the intermediate 7.65 calibre model (the Model 1922) was considered outmoded compared to the other two - an attitude which was reflected in market demand. The 1923 model, however, was not officially adopted by the armed forces, thereby raising the problem of having to create a new product that would attract the interest of the military.

Out of this came the Model 1931, a gun with the excellent mechanical features of the 23 in a more compact design which was also much lighter since it was designed for the classic Browning 7.65 cartridge. This pistol can be considered as the forerunner to the very famous Model 1934, from which it differed in only three ways: the line of the handgrip; the grips themselves, which were made of wood; and mechanically in the lack of half-cock on the hammer.

Beretta Model 1931 pistol is a simple blowback operated weapon. It uses typical 'Beretta-style' open top slide design, with return spring located below the barrel. The barrel is stationary during firing, but can be easily removed for inspection or maintenance. Trigger is of single action type, with exposed hammer. Manual safety lever is located at the left side of the frame, above the trigger, and requires full 180o rotation to engage (lever pointing rearward, letter 'S' exposed) or disengage (lever pointing forward, letter 'F' or red dot exposed). The same safety lever is used as a slide lock during disassembly, to hold slide to the rear. There is no dedicated slide stop mechanism, but the slide remains open after the last shot, being captured in the open position by the magazine follower. The slide automatically closes itself on the empty chamber as soon as empty magazine is withdrawn. The single stack box magazine holds 8 rounds. Magazine release is located at the base of the grip.